Cardiac ablation system and method for treatment of cardiac arrhythmias and transmyocardial revascularization

ABSTRACT

A medical device, and related method, use epicardial ablators and detectors for intraoperative epicardial approaches to ablation therapy of cardiac conduction pathways. An epicardial gripper is sized to grasp the cardiac circumference or smaller structures on the epicardial surface of the heart. Ablators are disposed on the arms of the gripper for epicardial ablation of cardiac conduction tissue. In another embodiment of the invention, an electrode system includes a flexible, adjustable probe forming a loop for epicardial ablation. Ablators are provided on one or multiple surfaces of the probe for epicardial ablation of cardiac conduction tissue. In yet another embodiment of the invention, an endocardial ablator detection system provides an indicator adjacent an ablator on an endocardial catheter, and a detector on an epicardial probe. The epicardial probe detects signals transmitted by the indicator on the endocardial catheter to localize the position of the endocardial ablator relative to the epicardial surface. The surgeon uses this information for guidance in adjusting the position of the endocardial ablator according to therapeutic objectives of cardiac ablation.

BACKGROUND OF THE INVENTION

[0001] Tachycardia is a type of cardiac arrhythmia and is a serious,often-times, fatal condition characterized by rapid, uncontrolled, andineffective beating of the heart. Most tachycardia is one of two broadcategories: ventricular tachycardia (hereinafter VT) andsupraventricular tachycardia (hereinafter SVT). VT occurs in the lowerchambers of the heart, the ventricles, and frequently leads to seriouscomplications, including sudden cardiac death. Atrial fibrillation andflutter, forms of SVT, originate in the upper chambers of the heart, theatria, and often result in chest pain, fatigue and dizziness and, whilegenerally not life-threatening, is a leading cause of stroke in theUnited States.

[0002] Currently, many cases of VT and SVT are treated by drugs thatmodify the electrical characteristics of the heart tissue. However, thedrugs do not eliminate or may not completely control the arrhythmia. Inmany cases of sustained VT, implantable cardiac defibrillators are usedwhich deliver powerful shocks to the heart when fibrillation isdetected. Concurrent treatment with drugs is standard therapy and eachimplantation of a cardiac defibrillator, of which there may be more thanone per patient, is very expensive.

[0003] Some forms of SVT are treated by endocardial ablation, aminimally invasive procedure. During endocardial ablation, a mappingcatheter is passed through an artery or vein into the patient's heart tofind the site(s) of the arrhythmogenic tissue, the tissue from which thetachycardia originate. This same catheter or a separate catheter is usedto transmit sufficient energy to thermally damage the tissue either byheating or cooling. (FIG. 1)

[0004] In atrial fibrillation the regular pumping action of the atria isreplaced by a disorganized, ineffective quivering caused by chaoticconduction of electrical signals through the upper chambers of theheart. Although not immediately life threatening, atrial fibrillationmay cause up to a 30% reduction in cardiac output and can lead to moreserious conditions, including the formation of blood clots in the atriathat can dislodge and travel to the brain resulting in stroke.Currently, the only curative treatment for atrial fibrillation is thesurgical “maze procedure”, an open heart procedure in which the surgeonmakes several incisions in the right and left atria creating scar tissueto electrically separate portions of the atria. Despite clinical successof the maze procedure, it is time-consuming and demanding. The procedurerequires open heart surgery and is very expensive. Accordingly, only amodest number of maze procedures are performed annually in a limitednumber of centers.

[0005] Another use of ablation technology, either endocardial orepicardial, is transmyocardial revascularization. The creation of smallablation holes results in genesis of new blood vessels, providing asource of blood flow in areas of the heart not receiving sufficientblood.

[0006] The present invention provides another apparatus and method fortreating cardiac arrhythmia, that may be widely applicable. The presentinvention also provides an apparatus for transmyocardialrevascularization.

SUMMARY OF THE INVENTION

[0007] The present invention provides devices and methods for epicardialand endocardial approaches for myocardial ablation for treatment ofcardiac arrhythmias and myocardial revascularization.

[0008] One aspect of the invention provides a gripper for grasping theepicardial surface of the heart for the purpose of ablating cardiactissue. In one embodiment, the arms of the gripper are sized anddimensioned to substantially encircle the circumference of the heart ora portion of it, thereby stabilizing the gripper against the contractingheart. The ablators are sized and positioned on one or more of the armsof the gripper according to the location and geometry of the cardiactissue to be ablated.

[0009] In another embodiment, the gripper is sized and dimensioned toencompass structures on the surface of the heart. In yet anotherembodiment of this aspect of the invention, one arm of the gripper isinserted through an incision in the wall of the heart into one of theheart chambers. The other arm or arms of the gripper are positioned onthe epicardial surface to stabilize the heart. The ablators are locatedon an arm or arms in an array according to the location and geometry ofthe tissue to be ablated. In one embodiment, the gripper ablates boththe epicardial and endocardial surfaces.

[0010] In one embodiment, one or more of the arms may form an array. Oneembodiment of the array is a Y. Another embodiment of the array areloops or spokes.

[0011] Another aspect of the invention is an electrode system comprisinga probe in the form of an adjustable, flexible substrate forming asubstantially closed loop for epicardial ablation. In one embodiment ofthe invention, the loop is sized to substantially encompass a structureon the epicardial surface of the heart. In another embodiment, the loopis substantially sized to encircle the circumference of the heart. Thecross section of the probe may be round, oval, multifaceted or havemultiple radii. In one embodiment the probe does not encompass theentire circumference of a portion of the heart.

[0012] In another embodiment of this aspect of the invention, the sizeof the substantially closed loop comprising the probe is adjustable by apull string attached to one end of the probe. In another embodiment theprobe substrate comprises an elastomeric material. The loop of theelastomeric probe is adjustable by expanding or contracting the probe.

[0013] In another embodiment of this aspect of the invention, theelectrode system is sized and dimensioned for insertion through anendoscope or thoracoscope. In yet another embodiment, the electrodesystem includes attachments such as, for example, a cooling system incommunication with the probe or a gripping device such as a suctiondevice in communication with the probe.

[0014] In one particular embodiment of the invention, the electrodesystem comprises a glove and an ablator in communication with one ormore fingers of the glove.

[0015] The ablators of the electrode system are positioned generally tocorrespond to the cardiac tissue to be ablated. In one embodiment, theablators are positioned on the inner surface of the probe. In anotherembodiment, the ablators are positioned on more than one surface of theprobe. For example, the ablators may be positioned on the flat surfaceof a probe with a D-shaped cross section, on one semi-circle of acircular cross section, or on one or more surfaces of a rectangularcross section. The ablators may be located on one or more arms in anyconfiguration.

[0016] In a preferred embodiment of this aspect of the invention, theablators may be individually and independently activated. In anotherparticular embodiment, the ablators are removably attached to the probesubstrate.

[0017] Another aspect of this invention comprises an endocardialablator-detection and ablation system for performing transmyocardialablation. The ablator-detection and trans-myocardial ablation systemprovides an indicator located on an endocardial ablating catheteradjacent an ablator, and a detector located on an epicardial probe. Theindicator located on the endocardial ablating catheter transmits asignal indicating the position of the ablator on the catheter. Theepicardial detector receives the signal thereby localizing the relativeepicardial position of the ablator on the endocardial catheter. Ablatingenergy is applied when the ablator is appropriately positioned.

[0018] In one embodiment of the endocardial ablator detection system,the indicator is a magnet and the detector is a magnetic field detector.In another embodiment of the detection system, the indicator is a lighttransmitter, such as, for example, laser light, and the epicardialdetector comprises a light detector. In another embodiment of the systemthe indicator is a light source emitting fluorescent light and theepicardial detector detects light in the wavelength of fluorescence. Inyet another embodiment of the invention, the epicardial detectorcomprises an ultrasound detector, or an echocardiograph. In yet anotherembodiment, a magnet in the epicardial probe attracts a magnetic ormetallic element in the endocardial ablator, guiding the ablators intoposition.

[0019] In any aspect of the invention, cooling or ablating energy may beapplied by the ablators to ablate cardiac tissue. In one embodiment,cooling fluid travels via a lumen in the ablator and exits via smallholes carrying the fluid through another lumen that exits from thecatheter. The change in pressure or phase change results in cooling orfreezing. The ablating energy applied to ablate cardiac tissue in anyaspect of the invention may be thermal, radio frequency, direct current,ultrasound or laser energy.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a simplified and diagrammatic sagittal section view ofthe interior of the left side of the heart showing an endocardialablating catheter of the prior art within a large vessel and leftatrium;

[0021]FIG. 2A is a simplified and diagrammatic view of the anteriorsurface of the left heart and FIG. 2B is a simplified and diagrammaticview of the posterior surface of the right heart;

[0022]FIG. 3 is a view of an epicardial gripper with two moveable armsand ablators on both arms;

[0023]FIG. 4 is a view of an epicardial gripper with one moveable armwith ablators and one fixed arm;

[0024]FIG. 5A is a diagrammatic view of another embodiment of theepicardial gripper with one moveable arm and one fixed arm;

[0025]FIG. 5B is an enlarged view of a serrated surface of the ablator;

[0026]FIG. 6 is a diagrammatic view of another embodiment of theepicardial gripper with one moveable arm and two fixed arms and ablatorson the inner surface of all arms;

[0027]FIG. 7A is a diagrammatic view of another embodiment of anepicardial gripper with two moveable curvilinear arms;

[0028]FIG. 7B is a diagrammatic view of another embodiment of anepicardial gripper with two moveable arms in a Y-shaped array;

[0029]FIG. 7C is a diagrammatic view of another embodiment of anepicardial gripper with two loop-shaped arms;

[0030]FIG. 7D is a diagrammatic view of another embodiment of anepicardial gripper with two multi-element spokes as arrays;

[0031]FIG. 8 is a diagrammatic view of another embodiment of anepicardial gripper with two moveable arms and ablators on one of the twomoveable arms;

[0032]FIG. 9 is a diagrammatic view of another embodiment of anepicardial gripper with multiple ablators disposed on the inner surfaceof both arms of the gripper;

[0033]FIG. 10A-J is a cross sectional diagrammatic view of the variousarrays of ablators on the surface of the arm of the epicardial gripperor the surface of the probe of the electrode system;

[0034]FIG. 11A is a diagrammatic view of multi-element cooling ablatorsin a portion of the arm of the gripper;

[0035]FIG. 11B is a diagrammatic view of another embodiment of thecooling ablators;

[0036]FIG. 12A is a diagrammatic view of laser ablators in a portion ofthe arm of the gripper;

[0037]FIG. 12B is another embodiment of laser ablators wherein theablators are lenses in the arm of the gripper attached by optical fibersto a laser source;

[0038]FIG. 12C is another embodiment of laser ablation wherein theablators are optical fibers connected to a laser source;

[0039]FIG. 13 is a diagrammatic view of the adjustable, flexible probesubstantially forming a loop of the electrode system;

[0040]FIG. 14A is a diagrammatic view of the adjustable, flexible probesubstantially encompassing an auricle of the heart;

[0041]FIG. 14B shows a camera permitting visualization of the cardiacsurface;

[0042]FIG. 15 is a diagrammatic view of the surface of the probe withthe ablators arranged in a linear array;

[0043]FIG. 16A-B is a diagrammatic view of cooling ablators in a portionof the probe of the electrode system;

[0044]FIGS. 17A is a diagrammatic view of laser ablators in a portion ofthe probe of the electrode system;

[0045]FIG. 17B is another embodiment of laser ablators wherein theablators are lenses in the probe of the electrode system attached byfiber optics to a laser source;

[0046]FIG. 17C is another embodiment of laser ablation wherein theablators are optical fibers connected to a laser source;

[0047]FIG. 18A is a diagrammatic view of the pull-string adjustableflexible probe of the electrode system in open position;

[0048]FIG. 18B is a diagrammatic view of the pull-string flexible probeof the electrode system in closed position;

[0049]FIG. 18C is another embodiment of the pull-string flexible probe;

[0050]FIG. 19 is a diagrammatic view of the adjustable, flexible probemade of elastomeric materials;

[0051]FIG. 20 is a diagrammatic view of the spring-adjustable flexibleprobe of the electrode system;

[0052]FIG. 21 is a cross-sectional view of the myocardium andendocardial ablator detection system;

[0053]FIG. 22 is a cross-sectional view of the myocardium and aendocardial laser ablator detection system;

[0054]FIG. 23 is a cross-sectional view of the myocardium and anepicardial ultrasound imaging probe.

DESCRIPTION

[0055] Anatomy of the Heart

[0056] The heart as shown in FIG. I has at least two surfaces, an outersurface, the epicardium 20, and an inner surface, the endocardium 22.Numerous cardiac structures are identifiable on the epicardial surface20. For example, as illustrated in FIGS. 2A and B, the pulmonary artery24 and aorta 26 exit from the epicardial surface 20 at the base 28 ofthe heart. The apex 30 of the heart is the pointed end of the heartopposite the base 28 of the heart. The left atrium 32 and right atrium34 are readily identifiable by the left 36 and right 38 auricles. Theright ventricle 40 and left ventricle 42 are localized by identifyingthe left longitudinal groove 44 which runs from approximately the heartbase 28 to apex 30 on the epicardial surface 20. The coronary groove 46on the epicardial surface 20 separates the cardiac atria 32, 34 from thecardiac ventricles 42, 40. The great coronary vessels 48 are disposed inthe coronary groove 46.

[0057] The endocardium 22 lines the inside walls of both types of heartchambers, i.e., the atria and the ventricles as illustrated in FIG. 1.The endocardial surface 22 opposes the epicardial surface 20 and isseparated by the thick muscular wall of the heart, the myocardium 50.

[0058] In one aspect of the invention as shown in FIG. 3, an epicardialgripper 52 includes at least two arms 54 that pivot around each other ata pivot point 56. The arms 54 of the gripper 52 are each attached to arespective handle 58. In one embodiment as shown in FIG. 3 the arms 54are moveable relative to each other. In another embodiment shown inFIGS. 4 and 5, the gripper 52 may include two arms wherein one arm is amoveable arm 60 and the remaining arm is a fixed arm 62, relative to themoveable arm. The arms may be disposed at the end of a long barrel 59,for example as illustrated in FIG. 5. In another embodiment, in amulti-arm gripper, one or more arms 62 are fixed while the opposing oneor more arms 60 is moveable as shown in FIG. 6. Any number of arms iscontemplated, at least one of which is moveable.

[0059] In one embodiment, as illustrated in FIG. 5B, the ablationsurface, non-ablation elements in contact with the heart tissue or bothare serrated or irregular in contour to increase friction.

[0060] As shown in FIGS. 3-9, the arms 54 of the gripper 52 generallycomprise an elongate body pre-formed into a generally curved orcurvilinear shape. The shape corresponds to the geometry of theepicardial surface to be ablated.

[0061] The arms of the gripper are formed from an electricallynon-conductive, inert, material. Suitable materials for the armsinclude, but are not limited to, Pebax® polyethylene, or polyester.Other materials, with the above characteristics, which retain theirshape at body temperature are also contemplated. The gripper may beformed of shape memory materials, for example, nitinol. The gripper maybe enclosed within a sheath dimensioned for insertion through a smallorifice. After the gripper is inserted, the sheath is removed and thegripper arms assume a pre-formed shape.

[0062] Each of the arms of the gripper 52 have an inner surface 64 andan outer surface 66 defining a cross section. The cross section may besubstantially circular, semi-circular, rectangular, V-shaped, D-shapedor the cross-section may have multiple radii as illustrated in FIGS.10A-J. In one embodiment, ablators 68 may be positioned on the innersurface 64 as shown in FIGS. 3-9. Ablators ablate cardiac tissue.Ablation destroys or removes the function of tissue. In some casesablation is followed by revascularization of the cardiac tissue. Asshown in cross section in FIG. 10, in other embodiments the ablators aredisposed on one or more surfaces of one or more arms. In variousembodiments, as illustrated in FIGS. 3-9, ablators are positioned on oneor more moveable arms, one or more fixed arms, or both.

[0063] Ablators may be positioned on the arms in a variety of ways. Inone embodiment, the ablator is a single, linear ablator as shown inFIGS. 3-8. In another embodiment, multiple ablators may be arranged onthe arms in a patterned array, such as, for example, a linear array asillustrated in FIG. 9. The spacing of the ablators depend on thegeometry of the tissue to be ablated. The number of ablators and thedimensions of individual ablators may be determined by tissue geometry,the arm shape, and the requirement for arm flexibility. In oneembodiment, each ablator is preferably made of platinum, about 0.2-5 mmthick and about 1-5 mm long. In another embodiment, the platinum ispreferably 2 mm thick and preferably about 4 mm long. In yet anotherembodiment, the ablators comprise detachable, reattachable ablators.

[0064] In one embodiment, prior to securing the ablators to the arms,each of the ablators is attached to a low resistance conductor wirethreaded through holes in the arm. In one embodiment, the ablatingenergy in each ablator is individually controllable.

[0065] In another embodiment of the gripper as shown in FIG. 11A, theablators 68 are cooling elements as known to one skilled in the art. Thearms 54 of the gripper 52 have an interior lumen 72, the proximate end74 of the lumen 72 in communication with a connection port (not shown)in the handle 58. The lumen 72 communicates with a hollow cavity 78formed in the ablator 68. In FIG. 11B, inlet holes 69 connect theincoming fluid to a lower pressure object.

[0066] Cooling may be accomplished by the delivery of a fluid or gas tothe ablators 68 contained within the gripper arms. The cooling fluid mayrecirculate or exit via small holes in the arms. Cooling is achieved bydelivering fluid or gas to the arms via one or more tubes. The gas mayexit via one or more tubes. The fluid or gas may come in direct contactwith the ablators or be separated from the ablators by a surface.

[0067] The cryoablation gripper device may consist of one or moreelements consisting of a delivery tube for the entrance of the cryogen.As shown in FIG. 11B, there are one or more small orifices 69 at theablation surface. At these orifices the cryogen goes from a high to lowpressure creating the cooling. These may or may not be a pressure changeonly or a phase change (FIG. 11B). There may be one or more deliverytubes 74 and one or more tubes 75 that take the fluid or gas back to theproximal end.

[0068] In another embodiment, the ablators are lasers. In one embodimentshown in FIG. 12A, the laser ablators 80 are disposed along the innersurface 64 of an arm 54 in an array, such as a linear array. The lasers80 are attached to conductor wire 82 leading to an energy source 84. Inanother embodiment shown in FIG. 12B the laser ablators are lenses 86attached by fiber optics 88 to a laser source 84. In another embodimentshown in FIG. 12C the laser ablators are optical fibers 88 attached to alaser source 84. In another embodiment (not shown) the ablator is anultrasound transducer.

[0069] The gripper may have one or more suction elements. The suctiondevice consists of a small hole which is along the contact surface ofthe gripper. This hole is attached to a tube which exits from thegripper. Suction is achieved by creating negative pressure within thistube using an apparatus outside the body. In another embodiment thesesuction elements consist of suction cups which create suction whencontact pressure is applied.

[0070] In a preferred embodiment shown in FIG. 8, the gripper 52comprises two moveable arms 60 configured to act as a clamp. A lineararray of continuous or discontinuous ablation elements or a singlecontinuous linear ablator 68 is located on one arm 60. In clinical use,the arms 60 are disposed about the circumference of the heart on theepicardial surface. The arm with the one or more ablators is alignedsuch that the ablator is positioned over the tissue to be ablated. Theopposing arm without ablators is disposed on the opposite side of theheart to stabilize the gripper on the epicardial surface. In oneembodiment, when the alignment of the ablating arms with the myocardialtissue to be ablated is satisfactory as known by a skilled artisan,ablating energy is applied. Sufficient ablating energy is applied to theablators to ablate cardiac tissue as required.

[0071] In an alternate embodiment (not shown), the gripper comprises anablating arm and a non-ablating arm. The ablating arm is insertedthrough an incision made by a surgeon through the wall of the heart. Theablating arm is aligned with the region of the endocardial surface to beablated and the non-ablating arm is disposed on the epicardial surfaceto stabilize the gripper. When the ablating arm is aligned by thesurgeon with the endocardial surface to be ablated, sufficient ablatingenergy is supplied to the ablators to ablate the cardiac tissue asdesired.

[0072] The gripper device is designed to ablate cardiac tissues. Thegripper is able to maintain stable contact with the epicardial surfaceby partially or completely encompassing a circumference of a part of theheart. The ablation may be performed on any portion of the epicardialsurface with which the gripper has contact. The ability of the gripperto partially or completely encompass a circumference of a part of theheart creates stability and allows for contact by conforming to theepicardial surface of the heart. Ablation may be performed in a linearor curvilinear arrangement.

[0073] In another embodiment, the invention is an electrode system forepicardial ablation of cardiac tissue. As illustrated in FIG. 13 theelectrode system 90 comprises a handle 58. Attached to one end of thehandle 58 is a probe 92 comprised of an adjustable, flexible substrateforming a substantially closed loop. The loop is sized to substantiallyencompass a structure of the heart such as an auricle 38 as shown inFIG. 14. The probe 92 has at least one contact surface. At least oneablator 68 is positioned on at least one contact surface.

[0074] In one embodiment of the gripper, an ultrasound probe is placedon the inner surface of the gripper in order to assess contact with theheart surface and depth of ablation lesion.

[0075] In one embodiment of the gripper, an optical fiber with orwithout a lens is placed on the inner surface of the gripper in order toassess positioning and contact. The optical fiber is attached to acamera outside of the body. In one embodiment illustrated in FIG. 14B aminiature camera 91 is placed on the inner or other surface of thegripper in order to assess positioning and contact.

[0076] The probe 92 of the electrode system 90 is formed from anon-conductive, flexible, adjustable material. Suitable materials forthe probe include but are not limited to Pebax, polyethylene, polyester,polyurethane, silicone and Teflon. The probe may be formed of shapememory materials, for example, nitinol. The probe may be enclosed withina sheath dimensioned for insertion through a small orifice. After theprobe is inserted, the sheath is removed and the probe assumes apre-formed shape. As illustrated in FIGS. 10A-J, the probe comprises across section defined by the probe surfaces, at least one surface beinga contact surface. As illustrated in FIG. 10C or 10F, in one embodiment,the cross section of the probe may be substantially D-shaped. In otherembodiments shown in FIGS. 10A-J, the cross section of the probe may becircular, semi-circular, rectangular, V-shaped, D-shaped or the crosssection may have multiple radii.

[0077] The electrode system 90 includes one ablator or a plurality ofablators. The one or more ablators 68 positioned on the probe 92 isarranged in any array, such as a linear array. The spacing betweenablators 68 depends on the geometry of the cardiac tissue to be ablated.The number of ablators, position of the ablators, and dimension of theablators depend on the geometry of the cardiac tissue to be ablated, thesurface of the probe on which the ablators are placed and therequirements for probe flexibility. In one embodiment, as illustrated inFIG. 15, multiple ablators 68 are arranged in a linear array along onecontact surface of the probe 92, the probe 92 having a substantiallyrectangular cross section. In other embodiments as illustrated in crosssection of FIG. 10A, a single long ablator or multiple continuous ordiscontinuous ablator elements may be longitudinally disposed on onesemicircle of a probe the probe having a substantially circular crosssection. In still other embodiments as illustrated in FIGS. 10C-J, theablators may be positioned around the circumference of the probe, aroundthree sides of a substantially D-shaped probe, as multiple points, oraround one to three sides of a substantially rectangular probe.

[0078] In one embodiment, each ablator is attached to a low resistanceconductor wire threaded through holes in the probe. In anotherembodiment the ablating energy of each ablator is individuallycontrollable.

[0079] Each ablator is connected to a low resistance conductor wire.Energy may be delivered to one or more of these ablators at one time(simultaneous energy delivery) or energy may be delivered sequentially.Energy delivery may be delivered in a repetitive and sequential mannere.g. x ms for electrode 1, y ms for electrode 2, z ms for electrode 3,and so on, followed again by x ms for electrode 1, y ms for electrode 2,z ms for electrode 3 and so on where x, y and z are real numbers. Thetime between energy delivery between electrodes n and n+l may be 0 ms ora value greater than 0 ms.

[0080] Activation of the electrode energy delivery may be achieved by acontrol box which is manually activated or activated by an electroniccontrol. A microprocessor may be used to activate energy delivery.

[0081] One or more optical fibers may be organized in a linear (one ormore rows) or curvilinear array or other geometric pattern such as anoval along the inner surface of the gripper. These may be individuallyor simultaneously activated with laser energy.

[0082] In one embodiment of the electrode system 90 as shown in FIG.16A, the ablators 68 are cooling elements. The probe 92 of the electrodesystem 90 includes an interior lumen 72, the proximate end 24 of thelumen 72 in communication with a connection port in the handle (notshown) as is known to one skilled in the art. The lumen 72 communicateswith a hollow cavity 78 formed in the ablator. Cooling may beaccomplished by the delivery of a fluid or gas to the ablators containedwithin the probe. The cooling fluid may recirculate (FIG. 16A) or exitvia small holes in the device. Cooling is achieved by delivering fluidor gas to the arms via one or more tubes 74. It may exit via one or moretubes 75 as shown in FIG. 16B. The fluid or gas may come in directcontact with the ablators or be separated from the ablators by asurface. This surface may be thermally conductive or non conductive. Thecryoablation device may consist of one or more elements consisting of adelivery tube for the entrance of the cryogen. There are one or moresmall orifices 69. At these orifices 69 the cryogen passes from a highto low pressure creating the cooling. In the embodiment shown in FIG.16B there may be a pressure change only or a phase change. In theembodiment shown in FIG. 16A there is no pressure change.

[0083] In another embodiment, the ablators 68 are lasers. In oneembodiment shown in FIG. 17A, the laser ablators 80 are disposed alongthe inner surface of the probe in an array, such as a linear array. Thelasers 80 are attached to conductor wire 82 leading to an energy source84. In another embodiment illustrated in FIG. 17B, the laser ablators 80are lenses 86 attached by fiber optics 88 to a laser source. In anotherembodiment shown in FIG. 17C the laser ablators are optical fibersattached to a laser source.

[0084] In one embodiment (not shown) the ablators are ultrasoundtransducers. The ablators in another embodiment are made of platinum. Inone embodiment, the platinum is about 0.2-5 mm thick and about 1-5 mmlong. In another embodiment, the platinum is about 2 mm thick and about4 mm long.

[0085] The ablators of the electrode system provide ablating energy fromany energy source known in the art including, but not limited to, radiofrequency energy, laser energy, direct current, or ultrasound. Inanother embodiment the ablators may use low temperatures, achieved bycryogens, for example, to ablate cardiac tissue.

[0086] In one embodiment of the electrode system show in FIG. 18A and B,the loop of the probe may be adjusted by a pull-string 94 disposed in achannel 102 within the probe 92. Moving the end 98 of the pull-string 94in the direction of the arrow 96 shown in FIG. 18A, substantially closesthe probe loop as shown in FIG. 18B. In another embodiment, asillustrated in FIG. 18C, the pull-string 94 is attached to the end 120of probe 92, and passes through a collar 126. Moving the end of thestring 94 in the direction of the arrow 96, adjusts the size of theprobe loop. In another embodiment shown in FIG. 19 the probe iscomprised of an elastomeric material for adjusting the size anddimensions of the loop. In yet another embodiment shown in FIG. 20 ofthe electrode system 90, the size and dimensions of the loop is adjustedby springs 100 or elastic material interposed between ablators 68 on theprobe 92 surface.

[0087] In another embodiment, attachment devices may be in communicationwith the probe, for example, a gripping device, such as a suctiondevice. The probe may have one or more suction elements. The suctiondevice consists of a small hole which is located along the contactsurface of the probe. This hole is attached to a tube which exits fromthe probe. Suction is achieved by creating negative pressure within thistube using an apparatus outside the body. In another embodiment thesesuction elements consist of suction cups which create suction whencontact pressure is applied.

[0088] In still another embodiment, the electrode system comprises aglove having at least one ablator on a probe, the probe being incommunication with the finger on the glove. In another embodiment theprobe and ablators may be in communication with multiple fingers of theglove. The ablators are placed on one or more surfaces of the glove. Theablators may be arranged in a linear or curvilinear array. Theseablators may be on the inner or outer surface of the curvature of theglove. For example, electrical ablator conductor wires are attached tothe ablators and exit from the glove to the energy source. In anotherembodiment using lasers, optical fibers are positioned on the surface ofthe glove and exit from the glove to the laser source. In anotherembodiment using cryoablation, the individual or single cryoablationprobe or elements are attached to surface of the glove and exit from theglove to the source of the cryogen.

[0089] In one embodiment, the electrode system is sized and shaped forinsertion through an endoscope or thoracoscope.

[0090] The gripper and the flexible electrode are used to createmyocardial ablative lesions from the epicardial and/or endocardialsurface of the heart. These devices are placed in contact with theepicardial surface of the heart and energy is delivered. Contact ismaintained because of the shape of the device and the ability of thedevice to conform to and be stabilized on the epicardial surface of theheart via friction, or suction.

[0091] Another aspect of the invention comprises a system for detectionof ablators localized on endocardial ablating catheters and relateddevices. The ablator detection system 101, illustrated in FIG. 21,comprises a detector 106 at the epicardial surface 20, at least oneindicator 104, at least one ablator 68, an endocardial catheter 108adjacent the endocardial surface 22 and an epicardial probe 110. Inanother embodiment the detector 106 is present adjacent to theendocardial surface 22 and the indicator 104 is on the epicardial probe110.

[0092] Referring again to FIG. 21, a system 101 for detection ofendocardial ablators localized on endocardial ablating catheters 108includes an indicator 104 localized adjacent an ablator 68 positioned onthe endocardial catheter 108 and a detector 106. The indicator 104transmits signals indicating the position of the ablator 68 on theablating catheter 108 inserted into a heart chamber 112. A detector 106positioned on an epicardial probe 110 detects the position of theendocardial indicator 104 adjacent the ablator 68 on the endocardialcatheter 108. When the ablator 68 is appropriately aligned with thecardiac tissue to be ablated as detected by the epicardial detector,ablating energy is applied to ablate myocardial tissue through theendocardium 22. In another embodiment the detector 106 is on theendocardial catheter 108 and the indicator 104 is on the epicardialprobe 110.

[0093] In one embodiment, the indicator 104 and/or the detector 106 is amagnet. A magnet may be present within or attached to the endocardialcatheter and the epicardial probe. In another embodiment either theendocardial catheter or epicardial probe have a magnet and the otherelement has a metal attracted by a magnet. The magnet may be a naturalmagnet or an electromagnet. The polarities of the magnets are selectedso that the endocardial and epicardial magnets metal or elementsattract. The endocardial catheter or epicardial probe may be positionedso that they are precisely aligned by using one or more magnets witheach element.

[0094] In another embodiment, the indicator is a light source, forexample, laser light. In one embodiment, there is no detector on theepicardial surface. The light is seen by the operator visually. Inanother embodiment there is an optical fiber on the epicardial probe todetect the light from the indicator. The optical fiber may be connectedto a video camera. In another embodiment a miniature video camera isplaced on the epicardial probe. The light source on the catheter may becircumferential or only on one surface of the catheter. In oneembodiment, the light source is on only one surface and the electrode orenergy elements are only on the same surface to permit alignment. Thedetector 106 is positioned on an epicardial probe 10. The probe 110 issized to fit a hand, formed from a flexible, inert substrate anddimensioned to abut an epicardial surface. In one embodiment, probes maybe cylindrical and held like a pen with the interfacing regionpositioned at the end of the probe. In another embodiment, the probe maybe rectangular or cylindrical with the interfacing region positioned onthe side of the probe. In one embodiment, the detector is a magneticfield detector. Alternatively, in another embodiment the detector is alight detector. In still another embodiment the detector is anultrasound device or an echocardiograph. In one embodiment theultrasound is used to detect contact with cardiac tissue and depth oflesion ablation.

[0095] In one embodiment ablators are present only on the endocardialcatheter or the epicardial probe. The endocardial catheter or epicardialprobe are used for positioning and orientation. In one embodiment theendocardial catheter is oriented so that ablation, for example laserablation, is directed towards the epicardial surface (FIG. 22). In oneembodiment the indicator is only on one surface, the surface of theablation elements.

[0096] The endocardial catheter is any endocardial ablating catheterknown in the art.

[0097] In a clinical application of the ablator detection system, theendocardial ablating catheter is passed through a patient's artery orvein into the heart to the site of arrhythmogenic tissue.Simultaneously, the epicardial detector probe is placed by the surgeonon the epicardial surface of the heart. The indicator positionedadjacent to the ablator on the endocardial catheter transmits signalsacross the myocardium to the epicardial surface. The signals transmittedby the indicator are detected by the detector on the epicardial probethereby localizing the position of the endocardial ablator relative tothe epicardial surface. The position of the endocardial ablator isadjusted in accordance with its relative position on the epicardialsurface and the therapeutic objectives of cardiac ablation. When theendocardial ablator is determined to be appropriately positioned,ablating energy is applied to cause trans-myocardial ablation.

[0098] An epicardial ultrasound imaging probe of dimensions suitable tobe inserted in a thoracoscope is used to visualize the anatomy of theheart tissue from the epicardial surface to provide ablation (FIG. 23).

What is claimed is:
 1. A gripper device for cardiac ablation comprising:at least one moveable arm having an inner and outer surface; and, one ormore ablators disposed on said inner surface of said moveable arm. 2.The gripper device of claim 1 wherein said ablator comprises a directcurrent electrode.
 3. The gripper device of claim 1 wherein said ablatorcomprises a radio frequency electrode.
 4. The gripper device of claim 1wherein said ablator comprises an ultrasound transducer.
 5. The gripperdevice of claim 1 wherein said ablator comprises a laser.
 6. The gripperdevice of claim 1 wherein said ablator comprises a cryogenic probe. 7.The gripper device of claim 1 wherein said plurality of arms isdimensioned for insertion through an endoscope.
 8. The gripper device ofclaim 1 wherein said device is dimensioned for insertion into acatheter.
 9. The gripper device of claim 1 wherein said inner surface ofat least one of said arms is serrated.
 10. The gripper device of claim 1wherein said ablator is serrated.
 11. The gripper device of claim 1wherein at least one of said arms is dimensioned and shaped to grip theepicardial circumference.
 12. The gripper device of claim 1 wherein saidone or more ablators are disposed along said at least one arm in ageometric pattern.
 13. The gripper device of claim 1 wherein saidablator comprises a linearly disposed plurality of electrodes.
 14. Thegripper device of claim 3 wherein said ablator comprises a linearlydisposed plurality of electrodes.
 15. The gripper device of claim 1wherein said ablators comprise one or more optical fibers connected to alaser source.
 16. The gripper device of claim 1 wherein the device ismade of shape memory materials.
 17. The gripper device of claim 1wherein an ultrasound imaging probe lies on the inner surface of thegripper.
 18. The gripper device of claim 1 wherein a miniature videocamera or optical imaging fiber lies on the inner surface of thegripper.
 19. The gripper device of claim 1 wherein said ablator islocated on at least two of said arms.
 20. A method for epicardialablation comprising the steps of: gripping said epicardial surface witha gripper device comprising a plurality of arms, each arm having aninner and an outer surface, wherein at least one of said arms ismoveable; and, an ablator wherein said ablator is disposed on said innersurface of at least one of said moveable arms; and applying said ablatorto said epicardium such that cardiac conductive tissue is ablated. 21.The method of claim 20 wherein said step of applying said ablatorcomprises applying radio frequency energy to said ablator.
 22. Themethod of claim 20 wherein said step of applying said ablator comprisesapplying DC current to said ablator.
 23. The method of claim 20 whereinsaid step of applying said ablator comprises applying a cryogenic fluidto said ablator.
 24. The method of claim 20 wherein said step ofapplying said ablator comprises applying laser energy to said ablator.25. The method of claim 20 wherein said step of applying said ablatorcomprises applying ultrasound energy to said ablator.
 26. An electrodesystem for epicardial ablation comprising: a probe comprising, anadjustable, flexible substrate, forming a substantially closed loop, theprobe having a cross section and at least one contact surface; and atleast one ablator located on the at least one contact surface of theprobe, wherein the loop is sized to substantially encompass a structureof the heart.
 27. The electrode system of claim 26 wherein the loop issized to substantially encompass an epicardial structure.
 28. Theelectrode system of claim 26 wherein said ablator on said probe ispositioned on at least two of said contact surfaces.
 29. The electrodesystem of claim 26 wherein the cross section of the probe issubstantially D-shaped and the at least one ablator is positionedsubstantially on the flat surface of the D-shaped cross section.
 30. Theelectrode system of claim 26 wherein the cross section of the probe issubstantially circular and said ablator is positioned on one semicircleof the circular cross section.
 31. The electrode system of claim 26wherein the cross section of the probe is rectangular and the at leastone ablator is positioned on the at least one surface of the rectangularcross section.
 32. The electrode system of claim 26 wherein said atleast one ablator comprises a plurality of ablators, and each of saidplurality of ablators is individually actuateable.
 33. The electrodesystem of claim 26 wherein said probe further comprises a first end anda second end, wherein the diameter of said loop is adjusted by apull-string attached to one end of said probe.
 34. The electrode systemof claim 26 wherein the at least one ablator comprises a plurality ofablators and elastic elements interspersed between and connecting pairsof the plurality of ablators.
 35. The electrode system of claim 26wherein said probe is removably connected to a handle.
 36. The electrodesystem of claim 26 wherein said at least one ablator is a direct currentelectrode.
 37. The electrode system of claim 26 wherein said ablator isa radio frequency electrode.
 38. The electrode system of claim 26wherein said ablator is an ultrasound transducer.
 39. The electrodesystem of claim 26 wherein said ablator is a laser source.
 40. Theelectrode system of claim 26 wherein said ablator is a cryogenic probe.41. The electrode system of claim 26 wherein said probe is dimensionedfor insertion through an endoscope.
 42. The electrode system of claim 26wherein said probe is dimensioned for insertion through a thoracoscope.43. The electrode system of claim 26 wherein at least one of saidcontact surfaces of said probe is serrated.
 44. The electrode system ofclaim 26 wherein said adjustable flexible substrate comprises an elasticmaterial.
 45. The electrode system of claim 26 wherein said probefurther comprises a cooling system in communication with said contactsurface of said probe.
 46. The electrode system of claim 26 wherein saidprobe further comprises an attachment device in communication with saidcontact surface of said probe.
 47. The electrode system of claim 46wherein said attachment device comprises a suction device incommunication with said contact surface of said probe.
 48. The electrodesystem of claim 46 wherein said attachment device comprises a grippingdevice in communication with said contact surface of said probe.
 49. Anelectrode system comprising: a glove; and, a probe comprising anadjustable, flexible substrate, the probe having a cross section and atleast one contact surface; at least one ablator located on the at leastone contact surface of the probe, wherein said probe is in communicationwith said glove.
 50. The electrode system of claim 49 wherein said probeis in communication with at least one finger.
 51. A method forepicardial ablation comprising the steps of: applying to the epicardiuman adjustable, flexible substrate forming a substantially closed probe,and having an inner surface; and, at least one ablator located on theinner surface of the probe, wherein the probe is sized to substantiallyencompass a structure of the heart; and ablating tissue within saidstructure of the heart.
 52. A method for epicardial ablation comprisingthe steps of: providing a glove comprising at least one ablator locatedon said glove; gripping the heart with said glove; and ablating cardiactissue with the ablator located on said glove.
 53. An electrode systemfor epicardial ablation comprising: a probe comprising an adjustable,flexible substrate forming a substantially closed loop, the probe havinga cross section and at least one contact surface; and, a plurality ofablators located on the at least one contact surface of the probe,wherein each of the plurality of ablators is removably attached to thesubstrate; and, wherein the loop is sized substantially to encompass astructure of the heart.
 54. A system for detecting the relativeepicardial location of an endocardial ablator comprising: an ablatorposition indicator located on an endocardial device; and, a detectorlocated on an epicardial probe, wherein said ablator position indicatorindicates the endocardial location of the ablator and the positiondetector detects the position of the ablator position indicator inresponse thereto, thereby localizing the endocardial ablator.
 55. Asystem for detecting the relative epicardial location of an endocardialablator comprising: an ablator position indicator located on anendocardial device; and, a position detector located on an epicardialprobe, wherein the ablator position indicator transmits a signal and theposition detector receives the signal transmitted by the ablatorposition indicator indicating the location of the endocardial ablator.56. The system of claim 54 wherein the indicator comprises a magnet. 57.The system of claim 54 wherein the detector comprises a magnetic fielddetector.
 58. The system of claim 54 wherein the indicator and detectorcomprise electromagnets.
 59. The system of claim 55 wherein theindicator is a radiofrequency signal and the detector is aradiofrequency detector.
 60. A system of claim 55 wherein the indicatoris only on one surface.
 61. The system of claim 55 wherein the indicatoris a light transmitter and the detector comprises a light detector. 62.The system of claim 55 where in the indicator comprises a transmitter oflaser light.
 63. The system of claim 55 wherein the indicator comprisesa light source emitting fluorescence.
 64. The system of claim 55 whereinthe detector comprises an echocardiograph.
 65. A method for detectingthe position of an endocardial ablation device and for transmyocardialablation comprising the steps of: indicating the position of anendocardial ablator with an indicator located on an endocardial device;detecting the position of the indicator with a detector located on anepicardial probe, wherein the detector detects the position of theindicator thereby localizing the endocardial ablator; and, applyingtransmyocardial ablation.
 66. The system of claim 54 wherein thedetector comprises a magnet.
 67. The system of claim 54 wherein thedetector comprises a magnet and the indicator comprises a metallicelement.
 68. The system of claim 54 wherein the indicator comprises amagnet and the detector comprises a metallic element.